我的checkbox值怎么取不到！！！！！急，在线等待
<script>
function checkOut(){
var chk=document.chkForm.miifmp.value
}
</script>


<form name="chkForm">
<td align="center">
<c:if test="${list.miifmp=='Y'}">
input type=checkbox name="miifmp" checked>
</c:if>
<c:if test="${list.miifmp=='N'}">
<input type=checkbox name="miifmp">
</c:if>
<c:if test="${list.miifmp==null}">
<input type=checkbox name="miifmp">
</c:if>
</td>
<input type="button" onclick="checkOut">
</form>

老是提示说是document.chkForm.miifmp为空或者不是对象，像这种一个checkbox，如何在js中获取它的值

谢谢！！！！！！！


[解决办法]
form name="chkForm">
<td align="center">
<c:if test="${list.miifmp=='Y'}">
<input type=checkbox name="miifmp" checked>
</c:if>
<c:if test="${list.miifmp=='N'}">
<input type=checkbox name="miifmp">
</c:if>
<c:if test="${list.miifmp==null}">
<input type=checkbox name="miifmp">
</c:if>
</td>
<input type="button" onclick="checkOut">
</form>


可以<input type=checkbox name ="miifmp" value="???" checked>